Information activity is often conducted before small groups of e.g. around ten individuals or less. In connection with such information activity, projectors of so called over-head-type often come to use. Such a projector must i.a. due to the small size of the group, not be too complicated, heavy or expensive. Should moreover ready portability be a desire, the choice often falls on a so called 3 M projector. In order to project a picture material by means of such a projector, the material, however, must normally be transferred to so called large dias, which is a time-consuming and expensive measure even if the picture material should be of suitable large dia size, i.e. A4.
Problem of having to transfer the picture material into large dia or the like, has been noted and has partly been given a solution through e.g. Swedish Pat. No. 397 140, which thus constitutes an indication on the stand point of the technique. However, such an apparatus is i.a. not readily transportable and is not useful in connection with small groups.